NOVA Online (click here for NOVA home)
Leopards of the Night
Site Map

Pit Viper Pit-viper

Pit vipers, along with several of their snake cousins, marry two senses to better locate prey at night: sight and a heat-detecting ability. Deep pits, which lie on each side of the snake's face between the nostril and the eye, are capable of sensing the warmth given off by a human hand held a foot away. Each pit has its own "field of vision" which overlaps slightly with the other, so that the pair work stereoscopically in the same way that eyes do.  Heat and visual data are sent, via the optic nerve, to the pit-viper's brain, where the two types of data are transposed into a single image.

What's different about the nocturnal eye?


Photo: Alan H. Savitzky/Old Dominion University.

Night Vision | Camera that Caught a Leopard
Behind the Scenes | Seeing through Camouflage
Resources | Transcript | Site Map | Leopards Home

Editor's Picks | Previous Sites | Join Us/E-mail | TV/Web Schedule
About NOVA | Teachers | Site Map | Shop | Jobs | Search | To print
PBS Online | NOVA Online | WGBH

© | Updated November 2000